Soldiers at the scene confirmed the find as they closed off the road while sappers worked to make safe the bomb.
The US military has declined comment but witnesses said at least one other device was found.
Wolfowitz is one of the architects of the US-led war on Iraq.
Details of his trip were not forthcoming but he is expected to try to boost morale among US occupation soldiers.
His visit, the second since April, coincided with a report released by a team of independent policy experts which advised the Bush Administration to get its act together within three months before Iraq descends into chaos.
The experts sent by the Pentagon to assess the post-war situation in Iraq also urged the administration to secure greater international involvement in the reconstruction process.
The US has repeatedly rejected a greater United Nations role in the rebuilding of the country and major powers have rejected sending troops as part of an international force without a UN mandate.
In their report, the experts said "the next three months are crucial to turning around the security situation, which is volatile in key parts of the country," but added the US needs to be prepared to stay there for several years.
US occupation troops have increasingly been targeted by resistance groups which has had a negative impact on the morale of the soldiers.
US occupation troops are
suffering mounting casualties
In a taped message believed to be that of the toppled Iraqi president, Saddam Hussein warned Americans to expect more resistance.
Hours after that message was broadcast on an Arab satellite channel, Aljazeera reported a group calling itself the Iraqi Resistance Brigades saying it was not linked to the former government.
The IRB said its operations are aimed at ending the US-led occupation.
The US has blamed Saddam loyalists for the attacks - the latest of which took place in the northern city of Mosul.
Two US soldiers were wounded when hand grenades were thrown at their checkpoint, Aljazeera reported.
Our correspondent added the soldiers shot dead the four attackers.
In Baqubah, northeast of the Iraqi capital, rocket-propelled grenades were fired at two US tanks in the town early Friday, causing no injuries, witnesses told AFP.
US forces also received a warning from tribesmen from the al-Jabour family in the town of Doura, south of Baghdad.
They want the soldiers to release a woman detained in the town or else face "escalating attacks", Aljazeera reported.
Warnings of escalating violence were also made in the Pentagon-commissioned study by the Council on Foreign Relations and the Centre for Strategic and International Studies.
"If Iraqis do not see progress on delivering security, basic services, political involvement and economic activity, the security situation will likely worsen and US efforts and credibility will falter," the report said.
The policy experts also stressed the need to involve more Iraqis in the rebuilding process as well as the need to ensure the success of the new Iraqi Governing Council.
The US-backed council was the target of criticism by 'Saddam' in his message broadcast on the 35th anniversary of the Baath party's rise to power.
The council's formation has also been denounced by a leading Shia cleric, Muqtada al-Sader.
Al-Sader told Aljazeera the council members should have been elected and not appointed by the US occupation administration.